I have been failing to render to a 3D texture for voxelization so I decided to go a slightly different route. I am able to create a FBO, and given a SINGLE clip plane, can render slices into the 3D...

Yes, the results differ between glReadPixels and glGetTexImage.

I have tested the program on a Radeon 6770M and a GeForce GTX 550 Ti, so I don't think it's a driver issue.

I'd like to avoid the...

glReadPixels is correctly returning the data in the FBO, but this does not always end up in the 3D texture. This is why I was lead to believe that glReadPixels will give me FBO data, but not...

I am trying to voxelize polygon meshes using a technique from Real-Time Volume Graphics p 319. The basis for this is using a FBO to render a bounding volume containing the mesh into a 3D texture. ...